– An Intro to Wind and Solar Power
– Geothermal and Heat Pumps
– Costs: Renewable Energy vs. Fossil Fuels
– Renewable Energy Create Jobs
– Environmental Impacts of Renewable Energy
– Challenges in a Transition to 100% Renewable Energy
– Access to Minerals for Renewable Energy
– The Capacity of solar and wind is less than fossil fuels
– Intermittency of renewable energy
– Siting Challenges
– Financial Challenges
– U.S. Government subsidies for Renewable Energy
– Renewable portfolio standards and state mandates or goals
– Renewable Energy Certificates or Credits (RECs)
– Net metering
– Feed-in tariffs (FITs)
– Upgrading the Grid
– Energy Efficiency
– Tidal and Wave Power
– Battery and Energy Storage
– Nature Based Climate Solutions
Transitioning to a Clean Energy Future
The world needs to create a sustainable energy system that relies on clean, renewable energy and conservation while ending greenhouse gas emissions as rapidly as possible.
Many believe that the best strategy is beneficial electrification, reducing energy demand across all sectors – electrical production, transportation, buildings, industrial processes – as much as possible, including with conservation and efficiency, and then electrify everything that remains.
However, virtually all actions have some negative environmental impact, including the building of wind and solar energy systems. Steps must be taken in all actions to minimize the negative impacts, including looking at how the product is disposed of once its useful life is ended. Projects must be carefully sited to reduce any negative environmental impact.
An Intro to Wind and Solar Power
One of the best introductory books that explains climate change is Fight the Fire: Green New Deals and Global Climate Jobs by Jonathan Neale. The Ecologist provides a free downloadable copy on their website. The chapter on Wind and Solar is pages 53 to 60.
Neale explains that wind turbines are built in three parts. On top of the “tower” sits the aluminum “nacelle,” which looks like a large oval submarine. Two or three large blades are attached to the front of the nacelle. The blades turn in the wind, driving a generator in the nacelle. Offshore wind turbines have become so large that they must be made at the port where they ships will take them to be installed. Having access to ships and ports able to transport the turbines has been a major barrier in the U.S. including the impact of the Jones Act, which imposes restriction on non-American ships.
Neale points out that there are three kinds of solar power – Solar PV (Photovoltaic), Concentrated Solar Power and Solar Thermal. Solar PV is the most important and is what most people mean when they refer to solar. Sunlight is made up of particles called photons. When those photons hit a wafer of silicon in the PV, they knock loose electrons, which flow down a wire that connects to the local electricity grid or a battery. Solar cells are thin slivers of silicon inside a plastic or glass cell that allows the light though. Those cells face the sun. While 90% of the cells are currently made with silicon, scientists are experimenting to find better or cheaper alternatives.
In March 2022, the US generated 18% of its electricity from wind and solar, up from 5.7% in 2015 (wind was the largest share). Wind and solar were the fastest-growing sources of electricity worldwide for the 17th year in a row in 2021. Many European countries generated more than 25% of their electricity from wind and solar in 2021, including Germany, Spain, and the UK. The International Energy Agency says that to reach net zero emissions, wind and solar need to reach 20% of global electricity by 2025 and 70% by 2050; it was 10% in 2021.
Hydropower accounts for an additional 6.3% of electricity in the US . Low-carbon nuclear accounts for about 19%. 
Offshore wind has been doing well in Europe for more than a decade but is only beginning to take off in the U.S., primarily on the East Coast. The first offshore wind project (only 5 turbines) in the U.S. was for Block Island in Rhode Island. The best offshore wind site in the world is off of NYC and Long Island. The federal government has just begun to sell leases there. Many of the initial companies are connected to European offshore wind farms. A study in 2013 by Stanford and Cornell professors found that NY could meet all of its energy needs by 2030 with renewable energy, including 40% coming from offshore wind.
Large-scale wind and solar farms are more cost-effective than small ones. Neale points out two reasons that make wind turbines ever larger. One, the amount of electricity produced increases with the square of the length of the blade, meaning if you double the length of the blade, you get four times as much electricity. (Triple it and you get 9 times more electricity), second, the amount of electricity produced increases with the cube of the wind speed. So, double the average wind speed, and you get eight times as much electricity. Double the length of the blade and triple the wind speed and you get 216 times as much electricity. Wind farms are built in very windy places, like mountain passes and ridges. Steady, strong wind is also the appeal of offshore wind farms.
Geothermal and Heat Pumps
Much of this section is taken from a report done by SHARE (Sheridan Alliance for Renewable Energy). SHARE is a coalition I helped start in 2017 to successfully defeat a proposal by the Governor of New York to add on new fracked gas turbines to power the State Capitol and complex to the century-old steam plant located in a low-income African American community. One of our main alternative proposals was to utilize geothermal energy study, using the nearby Hudson River – already used by the steam plant – as the heat source. 
Heat pumps offer an energy-efficient alternative to furnaces and air conditioners.  A major advantage of a heat pump is that it moves, rather than creates thermal energy. Instead of burning fossil fuels to produce warmth, a heat pump collects existing heat from the environment—either the ground, water, or air—and transfers it into a building. Conversely, for cooling, a heat pump transfers thermal energy within a building to the outside environment which functions as a heat sink.
Like a refrigerator, a heat pump uses electricity, which operates a compressor, and thermodynamics to maximize thermal energy delivered per volume. However, since heat is transferred rather than created, efficiencies exceed 100%. In fact, a well-designed ground-source or water-source geothermal system typically achieves heating efficiencies of 300% to 500%. This means that three to five times as many BTUs of beneficial thermal energy is provided compared to the amount of electricity required to run the system.
The Biden administration has become a major proponent of heat pumps. Biden used his Executive Powers under the Defense Production Act to boost the domestic production of heat pumps. The Inflation Reduction Act (IRA) that finally was approved by Congress in August 2022 included $8,000 rebates for heat pump purchases and $200 million to train contractors on installing heat pumps and other energy efficient appliances.
While some have argued that air source heat pumps (cheaper to install than ground source) don’t work well in cold temperatures, newer models are able to work in very cold temperatures, as Consumer Reports have written.  Such pumps are competitive with other heating sources, but their efficiency does decline as temperatures fall below freezing. In an air heat pump, outside air is blown over tubes filled with a refrigerant, warming up the refrigerant, and converting it from a liquid into a gas. This gas passes through a compressor, increasing the pressure. Compressed, hot gases pass into a heat exchanger, surrounded by cool air or water. The refrigerant transfers its heat to this cool air or water, making it warm.
Geothermal heat pumps have been in use since the late 1940s. They use the relatively constant temperature of the earth as the exchange medium instead of the outside air temperature. A few feet below the earth’s surface the ground remains at a relatively constant temperature. Depending on latitude, ground temperatures range from 45°F (7°C) to 75°F (21°C). This ground temperature is warmer than the air above it during the winter and cooler than the air in the summer.
Several techniques exist for thermal exchange with the outside environment. A common method is to drill vertical geothermal boreholes that allow for the transfer or thermal energy to and from the earth through circulation of a fluid in a closed loop. Each well is usually a few hundred feet deep and may also provide thermal storage. (Another technique involves installing a horizontal loop field within an excavated area, though this requires more land.) Closed-loop geothermal wells are commonplace for systems of every size, ranging from single-family residential homes to large-scale projects in which buildings are linked together in one or more districts—the largest of these in the US being Ball State University in Muncie, Indiana.
Geothermal district heating (GDH) is the use of geothermal energy to provide heat to multiple buildings and industry through a distribution network. The leading countries for GDH applications are China, Iceland, and Turkey. Iceland leads the world in GDH applications per capita. It is in its initial stage of development in the US but seems poised to expand rapidly, including at colleges. 
In addition to greater efficiency, an advantage of ground-source geothermal heat pump technology over air-source heat pumps is that all the outdoor infrastructure is below the surface. This makes it invisible and highly resilient. Wells can be located within open greenspace areas and courtyards, under sidewalks, and beneath parking lots without interfering with aesthetics or creating any permanent surface impact.
Costs: Renewable Energy vs. Fossil Fuels
In 2021, Lazard reported that wind power was 71% cheaper in 2020 than in 2009 while the cost of solar energy had dropped by 90%. In many cases, getting energy from new wind turbines and solar panels is now cheaper than getting energy from existing coal and gas plants.  Lazard said that when U.S. government subsidies are included, the cost for utility-scale solar is $27/MWh and $25/MWh for utility-scale wind, $42/MWh for coal, $29/MWh for nuclear and $24/MWh for combined cycle gas generation.
Having electricity from renewables be cost comparable or even cheaper than fossil fuels is key to speeding up their deployment. While the level of subsidies and tax credits provided by government for renewables has been critical, it is also subject to changing political decisions.
Many economists feel that imposing a carbon tax on the use of fossil fuels is the most effective way to speed up the transition to renewable energy (see chapter of carbon pricing). The carbon tax would reflect the cost of the damages caused by burning fossil fuels, including the significant health care costs from air pollution. The International Monetary Fund estimates that the annual subsidy provided by governments to fossil fuels is nearly 6 trillion, primarily (92%) due to the failure to charge for the health and environmental damages caused by burning fossil fuels. Yet most elected officials balk at imposing a carbon tax despite its merits; a main reason is the worry that voters will punish them for rising costs such as at the fuel pump or to heat homes.
One recent study found that each ton of CO2 pollution imposes $185 of damage — that’s more than triple the $55 estimate used by the federal government for the social cost of carbon.
The International Renewable Energy Agency tracked some $634 billion in energy-sector subsidies in 2020, and found that around 70% were fossil fuels, 20% for renewable power generation, 6% to biofuels and just over 3% to nuclear. (It should be noted that different agencies calculate subsidies in different methods and the level of subsidies fluctuate, especially with the price of oil)
Renewable Energy Create Jobs
Over 3 million Americans were employed by the clean energy sector as of 2020, compared to 1.2 million in the fossil fuel industry in 2019 (a drop of 2% from 2018). The clean energy sector added about 95,000 jobs each year from 2017 to 2019. California has the largest number of clean energy jobs, with 484,980 in 2020. Nevada saw a 38.9% increase in clean energy jobs from 2018 to 2020, the largest of any state. The clean energy median wage was $23.89 an hour in 2019, while the median wage for all industries was $19.14.
The 2022 U.S. Energy and Employment Report showed that the US’ clean energy industry is hiring faster than the overall national economy and is paying above-average wages.
Renewable energy employment worldwide reached 12 million in 2020, up from 11.5 million in 2019.  The clean energy transition is expected to generate 10.3 million net new jobs around the world by 2030, with the biggest impact felt in felt in modernizing energy infrastructure. The IEA estimates that a full net-zero clean energy transition would create a net of 22.7 million new jobs.
Many of the jobs in the clean energy transition will come from outside the electricity sector, starting with the decarbonization of buildings including massive insulation and the transition for heating and cooling from heat pumps and geothermal rather than gas and other fossil fuels.
Compared with fossil fuel technologies, which are mechanized and capital intensive, renewable energy is more labor intensive. Solar panels need humans to install them, and wind farms need technicians for maintenance. The means more jobs are created for each unit of electricity generated from renewable sources than from fossil fuels. 
Environmental Impacts of Renewable Energy
While renewable energy significantly reduces greenhouse emissions compared to the use of fossil fuels, they still have some negative environmental impacts. The production of renewable energy technology has some carbon footprint and can involve the use of hazardous materials. There is also the issue of what happens to the solar panels and wind turbines once they have exceeded their useful life.
Renewable energy often requires more land than fossil fuel production, which can include loss of farmland and forests or disruption of wildlife. Wind turbines, both land-based and offshore, kill migratory birds and bats from collisions. Hydroelectric dams can lead to high methane emissions from reservoirs and block migration routes for fish, preventing them from breeding and causing high juvenile mortality rates. Concentrating solar plants known as “power towers” produce beams of sunlight intense enough to incinerate insects and birds. Siting is often key to reducing the environmental impact. 
It is estimated that a utility-scale solar power plant will require between 5 and 10 acres per megawatt (MW) of generating capacity. Like fossil fuel power plants, solar plant development requires some grading of land and clearing of vegetation. Research from the National Renewable Energy Laboratory shows that powering the entire country with utility-scale solar would use 0.6% of the nation’s land mass – a significant amount. 
The Solar Star project in California is one of the largest solar energy farms in the world, with 1.7 million panels over 3,000 acres north of Los Angeles. A natural gas power plant 100 miles south produces the same amount of energy on just 122 acres. There is a growing movement, at least partially driven by false information and social media, to prevent solar developers from permitting new sites in rural America, both over concerns over land use (use of farmland, cutting of trees) and visual impact. The land for solar farms needs to be flat, dry, sunny, and near transmission infrastructure to hook into the grid. Opponents argue that solar developers are using the climate change issue to justify profit-making businesses that hurt the environment in other ways.
Many rural residents balk at such development in their communities when the electricity will be largely used for residents in large urban areas. And many agree that the first priority for siting should be on former brownfields (old factory and business sites) and on existing buildings and parking lots.
Many farmers, hard pressed to make a living, support solar farms as a way to supplement their income. Solar farms can still be used to farm crops and graze livestock. Studies have shown that it is beneficial to co-locate croplands and solar farms in a practice known as “agrovoltaics.” A farmer can easily revert their land to solely agricultural use if they decide to. Land not used for crops while a solar farm may even “maintain soil quality and contribute to the biodiversity of the land.” 
Solar energy can cut a farm’s electricity and heating bills, meeting the farms own energy needs. Solar heat collectors can dry crops and warm homes, livestock buildings, and greenhouses. Solar water heaters can also provide hot water for dairy operations, pen cleaning, and homes.to
One of the reasons to favor public ownership of energy is to give the public more control over siting issues. At a minimum, local governments should be proactive in engaging local residents to determine the best places to site solar and wind farms in their communities, rather than waiting for a private developer to select sites.
It is estimated a million birds are killed annually by wind turbines in the US. That pales in comparison to the number killed by collisions with communications towers (6.5 million); power lines (25 million); windows (up to 1 billion); and cats (1.3 to 4.0 billion). Birds are all lost due to habitat loss, pollution, and climate change. 
Still, wind turbines do kill birds and bats and steps should be taken to reduce the number. One step is to avoid siting the wind turbines in the migratory paths for birds. Others are looking at use of ultrasonic acoustic deterrents to protect bats from wind turbines.
As with solar, onshore wind farms usually need to be spread over more land than other power stations and need to be built in wild and rural areas, which raises concerns over the “industrialization of the countryside”. Conflicts have arisen in scenic and culturally important landscapes. Wind turbines also generate noise, and at a residential distance of 1000 feet this may be around 45 dB; however, at a distance of 1 mile, most wind turbines become inaudible. Some individuals may also be impacted by a strobe light effect by spinning blades.
Some ocean activists are also concerned that offshore wind farms will lead to the industrialization of the ocean while having a negative impact on marine habitat and fish, including the laying of transmission lines on and in the ocean floor and noise from construction. One of the earliest offshore wind farms suspended construction during half a year due to concern over negative impacts on the migration of whales.
Commercial fishermen have been among the most vocal opponents of offshore wind in the northeast, even though turbine platforms act as habitat for some fish species. Fishermen feel their concerns – which include safety issues operating around wind farms, fishing gear getting tangled with platforms or transmission cables, and how offshore wind development will alter the ocean environment and affect fish stocks – aren’t being considered by regulators. American fishermen are bracing for the sorts of conflict they have seen in Europe, where fishermen are often legally forbidden to operate in the vicinity of wind farms and subsea cables or have stopped due to safety and liability concerns. In the north-eastern US and mid-Atlantic, lease areas overlap with fisheries that add billions of dollars to regional economies.
Oceans are already under significant stress from climate change, overfishing, and pollution including extensive plastic waste. Many pesticides and nutrients used in agriculture end up in the coastal waters, resulting in oxygen depletion that kills marine plants and shellfish. Factories and industrial plants discharge sewage and other runoff into the oceans. Global warming is altering ocean chemistry and oceanic processes, and it is threatening many species of marine animals that cannot adapt to the higher temperatures. 
Environmental effects from hydropower vary widely. Reservoirs are a major source of emissions of methane from the decomposition of biomass. Dams can lead to habitat destruction. They can also block the migration of aquatic species and reduce sediment flow and nutrient transport.
There is a separate section that addresses the environmental impact of bioenergy.
Challenges in a Transition to 100% Renewable Energy
There are certainly skeptics who believe that ongoing political and NIMBY opposition, regulatory roadblocks, and consumer skepticism may make it impossible to upgrade the power grid fast enough to meet steadily increasing demand. Opposition could increase if a supply shortage leads to regular blackouts or calls to decrease energy usage. Others argue that there are too many periods when the sun isn’t shining, or the wind isn’t blowing for batteries to fill in the gaps. Building a new grid will require one of the biggest engineering efforts the U.S. has ever undertaken, beyond that even of the interstate highway system or electrifying the country. 
Access to Minerals for Renewable Energy
The world’s transition to zero emissions by building renewable energy, including electric vehicles, will spur a major increase demand for crucial metals such as lithium, cobalt, copper, nickel, and rare earth elements, with steeply rising prices and limited supplies. The mining and processing of these minerals are highly polluting and environmentally damaging.
China by far is the largest country for rare earth metal production, with the U.S. second. Native populations in the US and elsewhere are concerned about expanded extraction on their lands. Protests have occurred in Latin America, such as in Chile, over the mining of lithium.
A typical electric car requires six times the mineral inputs of a conventional car. An onshore wind plant requires nine times more mineral resources than a similarly sized gas-fired power plant. The International Energy Agency (IEA) predicts that the energy sector’s needs for critical minerals could increase by as much as six times by 2040, As the costs of technologies fall, minerals will be an increasing factor in renewable energy costs. While such minerals are widely scattered across the planet, the production and processing of many of these minerals are highly concentrated in a handful of countries, with the top three producers accounting for more than 75% of supplies. The increasing demand is already generating controversy over environmental and labor issues and indigenous rights as companies seek to extract the minerals in more remote and ecologically sensitive locations. 
The IEA has six key recommendations for policy makers, include the need for governments to commit to emission reductions, which would provide the confidence needed for suppliers to invest in mineral production. “Governments should also promote technological advances, scale up recycling to relieve pressure on primary supplies, maintain high environmental and social standards, and strengthen international collaboration between producers and consumers.” 
The recent vehicle federal tax credit in the IRA has requirements to promote EVs being manufactured in North America, as well as provisions as to where the materials are sourced from. The EVs’ batteries must be made with materials sourced domestically, or from a country that has a free trade agreement with the US. By 2026, vehicles will need to have 80% of critical materials sourced based on the rules. The U.S. doesn’t have the battery material mining operations in place to meet the growing demand. It will take some time for the country to catch up on lithium extraction and processing. 
The Capacity of solar and wind is less than fossil fuels
Capacity measures how often a plant is running at maximum power. Nuclear has the highest capacity factor, 92% in 2021, of any energy source. That’s nearly twice as much as a coal (49.3%) or natural gas (54.4%) plant and nearly 3 times more than hydro (37.1%), wind (34.6%) and solar (24.6%) plants.
The lower numbers for renewables reflects that the wind does not always blow (though better offshore), the sun does not shine at night, and water flow is dependent on factors such as rain.
While Capacity is not the same as electricity generation, it does tell you how big you have to build an energy facility to produce the amount of electricity you need.
Intermittency of renewable energy
The intermittency of renewable energy (e.g., no solar at night) has raised concerns over potential supply shortages, with fossil fuel companies arguing that they are needed to provide reliability to the electric supply, preventing blackouts and brownouts.
Scientists such as Mark Jacobson of Stanford point out that technological solutions exist to keep the electricity grid stable. One good mix is to link solar and wind, particularly offshore wind, as wind often blows stronger at night. Jacobson has studied this issue in 143 countries and documents that 100% renewable energy can stay stable everywhere in the world. One advantage is that using 100% renewable energy would significantly reduce energy needs, such as in buildings and by transitioning from gas-fueled vehicles to more efficient electric vehicle.
Offshore wind is usually less variable than onshore wind and often peaks when electricity demand peaks.  Wind turbines in cold climates also increases reliability because, on average, when temperatures drop and heating demand goes up, winds become stronger. Electricity storage is another grid-stabilizing strategy, saving excess production from renewable energy for later use. Present storage technologies include batteries, pumped hydropower storage, flywheels, compressed air storage, and gravity storage. In many places, solar plus batteries is already cheaper than coal or nuclear, with battery costs having declined 97% since 1991.
Another approach to the intermittency issue is to focus on demand. Efficiency improvements—such as switching to LEDs and insulating buildings—can reduce electricity consumption. Utilities can give financial incentives to encourage consumers to shift their energy use to periods when sunlight or wind is available.
According to the Federal Permitting Improvement Steering Council, permitting large solar projects takes nearly two and one-half years, while permitting electric transmission lines takes nearly three and one-half years.  The length of the permitting process however varies greatly from state to state. The “varied patchwork” of state, federal and local siting laws and regulations is a major obstacle facing the deployment of renewable energy.
“Not in my backyard” or “NIMBY” sentiments are another major obstacle to renewable energy infrastructure.
Siting of renewable energy has been a major problem in NY, with wind and solar projects often requiring ten years or more for approval. To try to reduce the time frame closed to two years, NY in 2020 passed a law strengthening the state’s ability to override municipal laws and regulations when those laws are found to be “unreasonably burdensome.” The state Office of Renewable Energy Siting will be responsible for overseeing the permitting process for renewable energy projects larger than 20 MW.
Under the new law, the local government review process is supposed to take only a year. Once a state determines the project is complete, the Siting Office will have 60 days to publish draft permit conditions. The public and municipality will then have 60 days to provide comment. Adjudicatory hearings, similar to evidentiary hearings, will be held if the public comments raise a “substantive and significant issue.” To respond to the concern that the state was overriding the historical commitment to local rule, it required the identification of “host community benefits,” such as discounts on utility bills.
In June 2022, California passed a law to streamline the approval process for large renewable energy systems.
At the federal level, the Bureau of Land Management’s solar and energy rule adopted during the Obama Administration promotes renewable projects through faster approval processes and development incentives.
Smaller renewable energy projects, including solar and wind farms, can also run into problems with local governments. Many local governments lack local zoning rules dealing with such projects and have often responded to community opposition to proposed projects by imposing a moratorium in order to give them time to “figure it out.” Local governments in states such as California, Indiana, Maine, New York, and Virginia have imposed moratoriums on solar farms.
Financing renewable energy has also been a challenge. Big fossil fuel companies both have deep pockets to self-finance and long-standing relationships with institutional lenders. Utilities are also already heavily invested in dealing with the fossil fuel and nuclear power infrastructure. Renewable energy often depends on federal and state government subsidies to make a project financially doable, but such subsidies can fluctuate from year to year, making both developers and lenders nervous about the long-term financial viability of a project.
Oil Change International estimates that the U.S. annually spends $37.5 billion subsidizing fossil fuels. Through direct subsidies, tax breaks, and other incentives, U.S. taxpayers help fund the industry’s research and development, mining, drilling, and electricity generation. Internationally, governments provide at least $775 billion to $1 trillion annually in direct subsidies, not including other costs of fossil fuels related to climate change, environmental impacts, military conflicts and spending, and health impacts. 
Renewable energy biggest costs are the upfront initial capital investment. Its operating costs are lower than fossil fuels since their energy supply – such as wind and the sun – are free. The costs for construction of solar and wind continue to decline though still somewhat above natural gas.
Switching from fossil fuels to renewable energy could save the world as much as $12 trillion by 2050, an Oxford University study says. Researchers say that going green now makes economic sense because of the falling cost of renewables. While wind and solar are already the cheapest option for new power projects, questions remain over how to best store power and balance the grid.
There way US renewable tax credits are designed also present challenges for developers. Tax breaks are supposed to go to companies that develop renewable energy projects, but these developers rarely owe any taxes as a new company, with no pre-existing tax bills to write the credits off of. To utilize the tax breaks, they often need to bring on third-party financial partners – typically large banks – selling their tax breaks in return for the upfront funding from the banks. 
The International Renewable Energy Agency reported that “renewable energy projects, especially in developing countries, face multiple challenges from the institutional, policy and regulatory level to the market and project level which can hinder the development and uptake of renewable energy. The latter include lack of market transparency, lack of financing and experience in project development, and lack of relevant information on regulations, markets, and resource availability.” 
Globally, investment in clean energy grew by only 2% a year in the five years after the 2015 Paris climate accords. But since 2020, the pace of growth has sped up significantly to 12%, with critical fiscal support from governments. It has also been aided by the rise of sustainable finance, especially in advanced economies. However, clean energy spending in developing economies (excluding China) remains stuck at 2015 levels. A troubling sign is the 10% rise in investment in coal in 2021, led by emerging economies in Asia, with a similar increase expected in 2022. Clean energy investment accounts for only around 5% of oil and gas company capital expenditure worldwide, up from 1% in 2019. 
Renewables dominate investment in new power generation and accounted for 70% of 2021’s global total of $530 billion spent on all new generation capacity. The U.S. added 462% more electricity from renewables than fossil fuels in the first half of 2022 compared to 2021, according to the U.S. Energy Information Administration (EIA).
Investing in renewable energy stocks outperformed fossil fuels by more than threefold in the last decade. Investing in green power was also less volatile in advanced markets.
U.S. Government subsidies for Renewable Energy
The 2022 Inflation Reduction Act (IRA) included the largest investments to date by the U.S. government for renewable energy. Some of the subsides for consumers include:
- $9 billion in home energy rebate programsto help people electrify their home appliances and for energy-efficient retrofits, with a focus on low-income consumers;
- 10 years of consumer tax creditsto make heat pumps, rooftop solar, electric HVAC, and water heaters more affordable, which make homes more energy efficient;
- $4,000 in consumer tax creditsfor lower- and middle-income individuals who buy used electric vehicles, and up to $7,500 tax credits for new EVs; and,
- $1 billion grant programto make affordable housing more energy efficient
The package includes more than $60 billion to support “onshore clean energy manufacturing” in the U.S. This includes:
- Production tax creditsto help U.S. manufacturers accelerate production of solar panels, wind turbines, batteries, and process key minerals;
- $10 billion for investment tax credits for new manufacturing facilities that make clean tech like EVs, wind turbines and solar panels;
- $500 millionto use the Defense Production Act to speed manufacturing of things like heat pumps, as well as processing critical minerals;
- $2 billion in grantsto help automaker facilities transition to clean vehicle production; and,
- Up to $20 billion in loansto construct new manufacturing facilities for clean vehicles.
There were various government incentives that existed before the IRA. Federal tax incentives included the Renewable Electricity Production Tax Credit (PTC), the Investment Tax Credit (ITC), the Residential Energy Credit, and the Modified Accelerated Cost-Recovery System (MACRS). Grant and loan programs are available from federal government agencies such as the Departments of Agriculture, Energy, and Interior. Most states also have some financial incentives available for renewable energy equipment. 
Renewable portfolio standards and state mandates or goals
A renewable portfolio standard (RPS) require that a percentage of electric power sales in a state comes from renewable energy sources. Some states have specific mandates for power generation from renewable energy, and some states have voluntary goals.
Most states have updated RPS targets of at least 40%. However, recent RPS legislation have pushed toward 100% clean or renewable energy goals. 10 states, D.C., Puerto Rico, and Guam have set 100% clean or renewable portfolio requirements with deadlines ranging between 2030 and 2050. Three states, plus the U.S. Virgin Islands, have goals of 50% or greater. 
Renewable Energy Certificates or Credits (RECs)
RECs allow a purchaser to pay for the generation of renewable electricity without directly obtaining the actual electricity from renewable energy sources. A renewable energy credits is created when a renewable energy source generates one MWh of electricity into the grid. RECs can be bought and sold, say to help a utility meet its RPS goals.
The climate impact of RECs is debatable. The sale of unbundled RECs (not tied directly to the electricity itself) is the most common form of green-power procurement in the voluntary market. U.S. sales of unbundled RECs jumped from 19.8 million MWh in 2010 to 68.7 MWh in 2019. Buying REC doesn’t always encourage the production of new wind or solar farms. it doesn’t necessarily help to displace fossil-based electricity, and it doesn’t do much to decarbonize the grid.  One study of major US corporations utilizing REC to support “net zero” policies found that while the companies claimed a 30% reduction in emissions, it was closer to 10%. 
Net metering allows residential and commercial customers who generate their own electricity from solar power to sell the electricity they aren’t using back into the grid. In effect, customers are allowed to run their meters backwards, putting any extra electricity say from a solar system on their house back into the grid. The enables them to avoid putting in their own battery storage system, which has limitations. During the day, most solar customers produce more electricity than they consume; net metering allows them to export that power to the grid and reduce their future electric bills.
As of 2021, 37 states and the District of Columbia have net metering for certain utilities, eight states have statewide distributed generation compensation rules other than net metering, and two states are in transition to statewide distributed generation compensation rules other than net metering. Two states do not have statewide rules, but some utilities in those states allow net metering. Most net metered systems are solar PV systems. In NY at least, net metering customers do not have to pay the “distribution” part of the utility bill, which is a significant savings.
Net metering is usually opposed by utility companies. One argument is that net metering makes other utility customers subsidize users of renewable energy; such users tend to be more affluent, raising charges for lower customers. There are ongoing efforts to repeal or reduce net metering rules. New York for instance has argued that as renewable energy develops, it makes more sense to modify such subsidies to provide greater support to renewable energy sources that are developed where they are most needed.
Proponents argue that “net metering policies create a smoother demand curve for electricity and allow utilities to better manage their peak electricity loads. By encouraging generation near the point of consumption, net metering also reduces the strain on distribution systems and prevents losses in long-distance electricity transmission and distribution. There are a wide variety of cost-benefit studies round the country that demonstrate the value solar provides to local economies and the electricity system as a whole.”
Feed-in tariffs (FITs)
FITs are long-term contracts to renewable energy producers that provide renewable energy producers an above market price. Providing price certainty and long-term contracts helps developers more readily obtain the needed financing. Usually FITs award different prices to different sources of renewable energy in order to encourage development of one technology over another. 
Several states and individual electric utilities in the United States have established FITS for certain types of renewable energy systems. FITs were more widely used in Europe to drive the development of renewable energy.
Ethanol and other renewable motor fuels
There are several federal and state requirements and subsidies for ethanol, biodiesel, and other fuels made from biomass. The federal Energy Independence and Security Act of 2007 requires that 36 billion gallons of biofuels be used in the United States per year by 2022. Several states have their own renewable fuel standards or requirements. Many states have their own programs for biofuels.
Upgrading the Grid
Once you have built a renewable energy power system, you have to get the electricity into the grid (transmission system) to deliver it to customers. Since renewable-energy sources often are based in more rural locations distant from cities where power is most needed, a high-voltage transmission infrastructure is needed to move the electricity across great distances. America’s transmission grid needs a major overhaul to make this happen, as well as making sure the transmission system is secure from extreme weather. A Princeton study determined that the U.S. must triple its transmission infrastructure in order to decarbonize by 2050.
New renewable energy systems often face exorbitant fees to connect to the existing grid. Nationwide, problems connecting to the grid is strangling new rooftop and community solar projects. The Solar Energy Industries Association reported community solar installations fell 21 percent and small commercial installations fell 10 percent in the third quarter of 2021 due in part to interconnection issues, 41 percent of community solar projects withdrew their applications to connect to the grid through the local utility Public Service Company of Colorado in 2019 and 2020. “Homeowners, business owners or nonprofits who are interested in solar are sometimes waiting several months — or years — to connect to the grid, which is typically operated by whichever electric utility serves the area. Long interconnection “queues” as well as a lack of transparency over wait times sometimes lead applicants to drop out of the interconnection process. “ 
Heat waves increases the demand for electricity to run air conditioners, straining electricity generators and power infrastructure. The drought in the west has meant less water to run hydropower and to provide the cooling needed for nuclear, coal, and natural gas. Wildfires can destroy transmissions lines; utilities sometimes proactively shut down transmission lines during wildfire conditions. Major storms like hurricanes can topple transmission lines.
The government needs to provide stronger leadership in the build out of the transmission grid. For instance, many power grid operators use historical weather patterns to make investment decisions, rather than the more dire climate projections, seeking to avoid the possibility of financial losses for investing in what might not happen.  Utilities often resent transmission operations because it weakens their ability to control local power markets; one Harvard researchers describes the transmission grid as a syndicate.
One solution would be for the government to take ownership and control of the grid to make sure it is built out properly and to eliminate issues about coordination among multiple grid owners. Public ownership would also lower costs since the profit margin would be eliminated. Others say that creating more microgrids and other distributed renewable energy systems is part of the grid solution.
Here is how the National Conference of State Legislators describes the grid challenge:
“Significant infrastructure upgrades will be required to address the needs of an evolving energy network. This includes upgrading existing transmission lines to incorporate distributed energy resources and building new lines to improve wholesale market operations, increase resilience and bring energy from remote renewable resources to population centers. The distribution grid—which carries energy to individual homes and businesses at the local level—will need even more investment than the transmission system. Sixty percent of U.S. distribution lines have surpassed their 50-year life expectancy, according to Black and Veatch, while the Brattle Group estimates that $1.5 trillion to $2 trillion will be spent by 2030 to modernize the grid just to maintain reliability.
“As more customers deploy distributed energy resources, some communities are seeing a fundamental shift in energy management, with large, distant generation sources being replaced by smaller, modular, and local sources. Creating a more flexible system—where customers can also be energy producers, energy managers and market participants—will require a much more adaptable and technologically advanced distribution grid. Developing a dynamic grid that can absorb and use the rapid expansion of distributed energy resources and other energy solutions will require advanced grid management technologies, digital controls and communications, new analytics, and supportive regulatory approaches, such as time-of-use pricing.
“Energy transmission, distribution and generation infrastructure are built to meet peak system needs, a costly approach since this may only occur for a few hours per year. New grid management approaches provide an opportunity to significantly decrease these peaks, reducing the infrastructure needed. Energy efficiency, energy storage, distributed generation, demand response, microgrids and new grid controls are already helping to reduce or eliminate the need for new transmission and distribution lines, substations, transformers, and other equipment.”
Amory Lovins of the Rocky Mountain Institute has long argued that investments in energy efficiency (not conservation) are by far the most cost-effective investment in a clean energy future. He argues for a mass investment in the insulation (and redesign) of buildings along with cheap renewables. He notes that since 1975, the cumulative energy saved by reduced intensity is 30 times the cumulative extra supply from doubling renewable output.
Lovins calls for “integrative, or whole-system, design,” a way to employ orthodox engineering to achieve radically more energy-efficient results by changing the design logic. For instance, by designing his own house to collect energy and to need no heating, he saves 99% of the space- and water-heating energy, and 90% of the electricity. And it was cheaper to build.
“If you make a car out of carbon fiber, you also save two-thirds of the investment in water and half the energy space and time needed to put the car together. And it needs a lot fewer batteries because it’s holding less weight because the carbon fiber is light…So if you do this across the whole economy, really designing whole systems in factories, equipment, buildings, vehicles, you’ll end up with severalfold larger energy savings than practically anyone now thinks is available. And the cost goes down.”
Cutting carbon emissions from challenging sectors like heavy transport and industrial heat will create new opportunities for business, argues Lovins. More than one-third of emissions come from heavy transport such as trucks and planes and the heat-intensive manufacture of materials such as steel and cement. Cheap renewables provide opportunities for new innovations. It is estimated that adopting circular economy principles could reduce emissions 37 percent for steel, 34 percent for cement and 56 percent for plastics. Rethinking the manufacturing process, a concept called integrative design, can minimize the need for materials. According to the International Energy Agency, we could save about 82 percent of steel and 90 percent of cement by comprehensive gains in efficiency by 2060. 
“The circular economy is based on three principles: Eliminate waste and pollution; Circulate products and materials (at their highest value); and Regenerate nature. It is underpinned by a transition to renewable energy and materials. A circular economy decouples economic activity from the consumption of finite resources. It is a resilient system that is good for business, people, and the environment.”
Investments in Energy Efficiency
Founded in 1977, the Alliance to Save Energy is “a nonprofit, bipartisan alliance of business, government, environmental and consumer leaders working to expand the economy while using less energy. Our mission is to promote energy productivity worldwide.”
Its recommendations include:
- Deploying energy-efficient technologies in end-use facilities and in power generation distribution can counteract the increased demand on and decreased output of power plants due to higher temperatures;
- Demand response and efficiency programs targeting peak loads can help counteract the increase in peak demand, thus reducing the need for additional power plants;
- Builders can “future proof” buildings against predicted changes in weather patterns by incorporating long-lived characteristics such as orientation, insulation and windows that are appropriate for expected climate conditions;
- Cities can reduce ambient temperatures, and make buildings more efficient, with cool or green roofs; and,
- Water efficiency programs can address climate impacts on water resources and reduce energy use for pumping and treating water.
The American Council for an Energy-Efficient Economy (ACEEE) develops transformative policies to reduce energy waste and combat climate change. They publish annual ratings of each state’s energy efficient steps along with recommendations for improvements.
ACEEE notes that most state climate policies, such as clean electricity standards and emissions reductions goals, have not addressed the important role of energy efficiency in plans to decarbonize state electric grids and economies. Policymakers should adopt rules that enable utilities to provide customers incentives for buying electric heat pumps, set building energy performance standards that spur energy-efficient retrofits, and invest in electric vehicle charging infrastructure coupled with comprehensive transportation efforts. They also recommend that energy-efficient investments be targeted to low-income populations to make the energy transition more equitable.
There is also a need to strengthen appliance energy standards to reduce energy demand while saving money. Unfortunately, consumer use of such standards has not been ideal, and the Trump administration sought to kill the energy STAR rating program.
States and the federal government could adopt stronger energy standards for appliances. In June 2022, the New York legislature passed a bill to require appliances to be more energy efficient. The law will apply to many common household products, including computers and televisions. It requires the state update energy and water efficiency standards for 7 products already regulated by the state and to set new standards for another 30, including air purifiers, electric vehicle chargers, and restaurant equipment. The new standards are estimated to save New Yorkers $800 million annually on utility bills by 2025, rising to $1.3 billion per year by 2030.
The Inflation Reduction Act passed in August 2022 made sizeable investments in energy efficiency. Below is an overview from ACEEE. 
Buildings: The IRA bill provides $9 billion for states to issue rebates to homeowners for whole-home retrofits and for efficient heat pumps, heat pump water heaters, and other electrical equipment. Most of those funds would be for low- and moderate-income households. The IRA also restored and greatly increased tax credits for heat pumps and smaller home improvements such as insulation and increased the tax deduction for commercial building retrofits. Tax incentives were increased for building highly efficient new homes and commercial buildings, including incentives for “zero-energy-ready” homes and buildings. The bill also gives $1 billion in additional aid to help states and cities adopt and implement strong building energy codes.
Transportation. The bill provides a new tax credit and additional funding for purchasers of electric trucks and buses, which lag behind electric cars and SUVs in deployment. The bill also includes a new $4,000 credit for purchasing used electric cars and SUVs, and it revives the $7,500 credit for new electric vehicles, which had been slowly expiring. However, there are concerns that new requirements for U.S. sourcing of materials and battery components, along with income caps on who can take the credit, will limit usage, particularly in the early years.
The bill does much less for other ways of moving passengers and freight or for broader transportation system efficiency. But it does include $3 billion for a new Neighborhood Access and Equity grant program supporting projects that improve walkability, reduce vehicle pollution, and help residents use affordable transportation to access essential services and green spaces, especially in disadvantaged and underserved communities. This would be the first program focused on transportation equity funded at this level.
Industry. Decarbonizing industry—a third of U.S. GHG emissions—will require effective energy management, transformative process technologies, use of electricity and low-carbon fuels, and shifts to use of materials responsible for lower life-cycle emissions. IRA would provide significant support for the initial deployment of key technologies.
The IRA includes almost $6 billion for grants and loans to companies that use innovative decarbonization technologies, like direct reduction of iron from ore using hydrogen instead of fossil fuels or inert anode aluminum production. IRA also allocates $10 billion for tax credits for transformative investments in manufacturing facilities and expands the credit to cover equipping an industrial plant to reduce GHG emissions by at least 20% (among other uses).
Tidal and Wave Power 
Tidal power uses the force of the tides to turn electric generators. This can be done by vertical or horizontal turbines under the sea in shallow waters. Tidal power can also use barrages to funnel the water through a narrow passage, though there is a concern that such barriers could negatively impact on marine life. While tidal power provides predictable power around the clock, it is still an expensive, developing technology. Presently, tidal power only makes sense in places where there are exceptional tides and still requires large subsidies.
Wave power makes sense in many more places but is still also in the experimental stage. it usually involves small turbines that bob near the surface that are linked in lines while anchored to the seabed.
Battery and Energy Storage
The development of ways to store electricity from intermittent renewable energy such as wind and solar is critical in the move to 100% clean energy. The sun doesn’t always shine, the wind doesn’t always blow, which is why large-scale storage must play a fundamental role.
The challenges for battery storage includes reducing the upfront cost and to increase the length of time the electricity can be stored.
According to a May 2022 report from MIT, almost all of world’s present large-scale energy storage capacity is pumped hydro. Water is collected in a reservoir and sent flowing downhill to turn into turbines when electricity is needed and prices for power are high. When electric demand is low and cheap, the energy is used to pump water back into the reservoir. The report also listed iron-air batteries, molten metal and thermal storage and flow-cell batteries. The use of excess renewables at low demand times to create hydrogen is another option.
The increasing research and investment in new battery storage technologies has led to rapid cost reductions, notably for lithium-ion batteries. In Germany, small-scale household Li-ion battery costs have fallen by over 60% since late 2014. The declining costs has opened up new applications for battery storage. A study by the International Renewable Energy Agency (IRENA) found that by 2030, total installed costs could fall between 50% and 60% (and battery cell costs by even more). Battery lifetimes and performance will also keep improving, helping to reduce cost of services delivered. Lithium-ion battery costs for stationary applications could fall to below $200 per kilowatt-hour by 2030. IRENA expects battery storage in stationary applications to grow from 2 gigawatts (GW) worldwide in 2017 (11 GW in 2020) to between 80 to 420 GWh in 2030, rivalling pumped-hydro storage.
California has the largest amount of utility-scale batteries connected to the grid in the U.S., reaching 3,163 MW by June 2022. Many additional large battery storage systems are in development, with more than 700 MW projected to be added in the summer of 2022. Such storage facilities make money on the price differences between times of charging when prices are low and discharging when prices are high because energy is scarce. 
A solar-plus-storage system is a battery system that is charged by a connected solar system, such as a photovoltaic (PV) one. From 2008 to 2017, the U.S. was the world leader in lithium-ion storage use, with about 1,000 MWh of storage, almost all by utilities. The average duration of such systems is 1.7 hours, but it can reach 4 hours. Batteries account for the biggest share of a storage system’s cost right now. A storage system contains an inverter and wiring in addition to the battery—and utilities will need big battery packs if they’re going to provide backup power for all customers. The system costs in 2019 ranged from $380 per kWh for those providing electricity for 4 hours to $895 per kWh for 30-minute systems.
Globally, factors pushing the development of storage include:
- “Grid modernization. The growth of battery storage goes hand-in-hand with grid modernization efforts, including the transition to smart grids. Batteries help to unlock the potential of smart technologies, and vice versa.
- Participation in wholesale electricity markets. Battery storage can help balance the grid and improve power quality regardless of the generation source. Nearly every nation examined is revamping its wholesale market structure to allow batteries to provide capacity and ancillary services.
- Financial incentives. Nations are increasing the availability of financial incentives for storage investment
- Phase-outs of FITs or net metering. Reduction of feed-in-tariffs (FITs) or net metering payments is driving behind-the-meter battery deployments in some countries, as customers strive to derive maximum value from their rooftop solar installations in the absence of these incentives.
- Desire for self-sufficiency. In Germany, for example, ecological motives, independence from utilities, resiliency, and technical curiosity are all thought to be motivations. Self-sufficiency is also a strong driver in Italy, the United Kingdom, and Australia.
- National policy. Many countries are turning to renewable energy storage to reduce dependence on energy imports, enhance the reliability of their systems, and move toward de-carbonization targets.”
Nature Based Climate Solutions
Nature-based climate solutions, such as reforestation, regenerative agriculture, and wetland restoration, employ natural processes to reduce greenhouse gas concentrations in the atmosphere and slow global warming.
Natural climate solutions help address climate change in three ways: reducing greenhouse gas emissions related to land use; capturing and storing additional carbon dioxide from the atmosphere; and improving resilience of ecosystems. 
Some nature-based solutions, such as conserving existing wetlands, mainly prevent greenhouse gas emissions. Others, such as restorative agriculture and regrowing clear-cut forests, actively remove CO2 from the atmosphere. Some do both.
See the chapter on agriculture for a number of nature-based solutions to our agriculture and food systems, as well as the issue of deforestation.
The IPCC estimates that, by 2030, up to a third of its annual land-based emissions reductions targets could be achieved at a cost of $20 or less per carbon ton.
The Nature-Based Solutions (NBS) Coalition, co-led by China and New Zealand launched the NBS for Climate Manifesto at the 2019 UN climate summit, with recommendations on 200 best practices and initiatives.
Much of the millions of acres of land that have been deforested provides little or no food production, allowing reforesting to sequester billions of tons of carbon dioxide without harming food production. In some cases, reforestation can be inexpensive and as simple as refraining from burning marginal grazing land, allowing forests to regenerate naturally. Reducing deforestation will require establishing large-scale incentives and regulatory mechanisms to address the major sources of deforestation, such as cattle ranching in the Amazon or palm oil production in Indonesia. 
Globally, coastal wetlands constitute 80 to 300 million acres. Much of those wetlands are degraded and in need of restoration. Coastal wetlands such as mangroves, tidal marshes, or seagrass beds can be restored by reducing pollution, replanting lost vegetation and/or by repairing the natural flow of water. Avoiding coastal wetland conversion is a low-cost climate mitigation pathway.
Ocean ecosystems serve as the largest carbon sink in the world. Ocean-based natural climate practices include restoring seagrass meadows or growing kelp or shellfish to restore or expand marine ecosystems. 
 P. 56-57. Fight the Fire, op cited
 https://sharealbany.org/wp-content/uploads/2019/07/SHARE-science-report-7-11-19.pdf, pp. 26 – 30
 https://www.sciencedirect.com/topics/engineering/geothermal-district-heating; and https://www.nrel.gov/news/press/2021/new-nrel-report-details-current-state-vast-future-potential-us-geothermal-power-heat.html
 https://www.theregreview.org/2022/03/16/miller-how-current-siting-regime-stifles-renewable-energy/; see also https://www.harrisbeach.com/insights/new-york-takes-action-to-expedite-renewable-energy-siting-and-development/
 https://priceofoil.org/fossil-fuel-subsidies/; and https://www.ucsusa.org/resources/barriers-renewable-energy-technologies
 https://www.seia.org/initiatives/net-metering; and https://www.seia.org/initiatives/solar-cost-benefit-studies
 https://www.governor.ny.gov/news/governor-hochul-signs-legislative-package-spur-energy-efficiency-consumer-savings-and; and, https://www.aceee.org/blog-post/2022/06/new-ny-appliance-efficiency-bill-will-save-consumers-money-and-cut-climate
 From Fight the Fire, pp. 66 – 67, https://theecologist.org/sites/default/files/2021-02/Fight_the_Fire_0.pdf
 https://www.irena.org/publications/2017/oct/electricity-storage-and-renewables-costs-and-markets; https://www.irena.org/news/articles/2020/Mar/Battery-storage-paves-way-for-a-renewable-powered-future