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Solar Water

Electricity Generation

Water heating is a major energy use. Solar water heaters use the sun's radiation and can reduce that energy consumption by 50 to 70 percent.

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Rank and results by 2050 #41

Solar Water

Reduced CO2: 6 gigatons
Net cost (Billions US$): $2.99
Net operational savings: $773.65 billion
What do these numbers mean?

TOTAL CO2-EQ REDUCTION (GT)

Total CO2-equivalent reduction in atmospheric greenhouse gases by 2050 (gigatons)

NET COST (billions US $)

Net cost to implement

SAVINGS (billions US $)

Net savings by 2050

Impact:

If solar water heating grows from 5.5 percent of the addressable market to 25 percent, the technology can deliver emissions reductions of 6.1 gigatons of carbon dioxide and save households $774 billion in energy costs by 2050. In our calculations of up-front costs, we assume solar water heaters supplement and do not replace electric and gas boilers.

Solar Water

Electricity Generation

Water heating is a major energy use. Solar water heaters use the sun's radiation and can reduce that energy consumption by 50 to 70 percent.

Water heating is a major energy use. Hot water for showers, laundry, and washing dishes consumes a quarter of residential energy use worldwide; in commercial buildings, that number is roughly 12 percent. Solar water heating—exposing water to the sun to warm it—can reduce that fuel consumption by 50 to 70 percent.

The world’s first commercial solar water heater came to market in the 1890s. In the early 20th century, the technology took a leap forward by adding a separate storage tank. Solar collectors popped up on rooftops across California and Florida, but cheap energy in the post–World War II years stymied the industry in the United States.

Today, the technology is in use in many countries and almost every climate. In Cyprus and Israel, where the use of SWH has been mandated since the 1980s, 90 percent of homes have systems. Throughout its history, SWH has risen and fallen based on the price of energy, as well as government intervention to support it.

All told, SWH is among the most effective ways to convert solar energy into thermal energy. Payback periods are as short as two to four years, depending on specifics of system and location.

Vs

Energy Storage (Utilities)

Electricity Generation

Energy storage — daily, multiday, and longer-term or seasonal — is vital to reduce emissions from polluting “peaker” plants and accommodate the shift to variable renewables.

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Rank and results by 2050 #77

Energy Storage (Utilities)

What do these numbers mean?

TOTAL CO2-EQ REDUCTION (GT)

Total CO2-equivalent reduction in atmospheric greenhouse gases by 2050 (gigatons)

NET COST (billions US $)

Net cost to implement

SAVINGS (billions US $)

Net savings by 2050

Impact:

Taken on its own, the production of energy storage does not reduce emissions; instead, energy storage enables adoption of wind and solar energy. No carbon impact numbers are included above in order to prevent double counting with the variable renewable energy solutions themselves. As with other forms of grid flexibility, the costs and total growth are not modeled directly.

Energy Storage (Utilities)

Electricity Generation

Energy storage — daily, multiday, and longer-term or seasonal — is vital to reduce emissions from polluting “peaker” plants and accommodate the shift to variable renewables.

Utilities have long operated on the model of producing sufficient electricity to meet demand in real time. To supplement large coal, gas, or nuclear plants, they rev up highly polluting “peaker” plants as needed. Energy storage — daily, multiday, and longer-term or seasonal — is vital to reduce peaker emissions and accommodate the shift to variable renewables, namely wind and solar.

How does a utility store large amounts of electricity? One option is pumping water from lower reservoirs into higher ones, ideally 1,500 feet higher. The water is released back down into the lower reservoir as needed and runs through power-generating turbines. There are more than 200 pumped-storage systems in the world at present, accounting for 97 percent of global storage capacity.

Concentrated solar power plants are also at the forefront of energy storage, where molten salt is used to hold heat until it is needed to generate electricity. Then, there are batteries at scale. Dozens of start-ups and established companies are racing to create low-cost, low-toxicity, and safe batteries that will revolutionize energy storage, while some utilities are already installing banks of lithium-ion batteries to help meet peak demand.

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