The weather’s warming up, which for many people means it’s time to hit the beach! While you’re out, you may notice a few things: the heat of the sun, the warm breeze, and the waves and tides that make playing in the ocean so fun. Not only are all three of these natural processes key ingredients for a wonderful day (or week!) off, they are also powerful sources of renewable energy. In this article, we look at how sun, wind, and waves generate power and their relative advantages and disadvantages to each other, so you can make an informed decision for your business. It’s summer! So sit back, relax, and let Holocene do the legwork for you.
Solar
Overview
The sun’s energy isn’t just a way to work on your tan – it’s heat can be converted into electricity for human consumption. Solar comes in two main types: thermal and photovoltaic. Thermal solar systems use the heat of the sun to run a heat engine that turns a generator and thereby produces electricity. Photovoltaic panels directly convert the sun’s light into energy. Solar panels can be ground mounted or roof mounted, and can be done on a large scale and sold into the grid (utility scale solar), or can be installed on individual homes and businesses in a distributed generation model. Most of the nation’s solar plants can be found on the East Coast (especially North Carolina, PJM, and New Jersey), Southern California, and the Southwest, with companies such as Ikea and General Motors investing in solar energy. Ikea has almost 700,000 solar panels on its stores and distribution centers worldwide, and General Motors uses a total of 48 megawatts of solar power spread across 22 facilities. Solar Power Purchase Agreements (PPAs) typically last 15-20 years. While solar is more expensive than wind (as of 2017, the levelized cost of electricity, or LCOE, is at USD 0.10/kWh for photovoltaics and USD 0.22/kWh for concentrated solar power), prices have been dropping consistently and rapidly over the last decade, with solar prices nearing those of wind and expected to drop even further as technology improves. Solar is a great choice for companies looking for versatility in their power portfolios, as solar can be installed almost anywhere and projects can vary in size, allowing companies to decide to buy all their energy from a single large solar source or to use smaller solar projects to supplement their energy portfolio. This also makes solar a great choice for smaller companies who don’t need the power provided by a 50 MW project, with many smaller sizes of solar projects on the market.
Pros
- Low O&M (operation and management) costs
- Can help offset peak loads, so less brown power is required to meet demand
- No emissions from energy production
- Rapidly decreasing costs
- Not very site-dependent
Cons
- Less effective on cloudy days
- Can’t generate power at night
- Requires considerable free/open space to produce sufficient amounts of energy
- Higher upfront costs (these are dropping rapidly, but still may be affected by the dissolution of subsidies)
Wind
Overview
In the not so distant future, you may go to the beach and see, far out in the water, wind turbines that generate energy using the same wind that gently ruffles the corners of your beach blanket (and gets sand all over everything). While many people default to onshore turbines when thinking of wind power, wind, like solar, comes in two main types: onshore and offshore. Onshore refers to wind turbines located on land, while offshore refers to turbines located in water. This water can refer to either the open ocean or a body of freshwater. When the wind blows, it turns the turbines; their turning is what generates electricity. Turbines themselves come in two types, Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines (VAWT). HAWTs are the most common, especially for commercial use, while VAWTs are commonly used for individuals and businesses and in places where the wind may be too turbulent for HAWT use as they sustain damage in high-velocity winds. Most wind projects are found in the Midwest, Texas, and New England. Major companies such Adobe and Nike use wind as part of their renewable energy portfolio, with Adobe signing a PPA for a 320 MW wind farm which also signed a major PPA with Facebook, and Nike signing its second major wind PPA for an 86 megawatt project in Texas in January 2018. Wind PPAs are typically 15-25 years, with the LCOE at USD 0.06/kWh as of 2017. While wind has traditionally been cheaper than solar, falling solar prices, combined with solar’s low impact on the visual landscape and ability to be installed in areas wind turbines cannot be installed, such as urban environments, have caused corporations to think beyond wind for their renewable needs. Wind has a few more geographic limitations than solar, and is considered at least, if not more, consistent. However, while solar panels convert light into energy even on a cloudy day (albeit in much smaller amounts), large turbines don’t blow in a slight breeze. A company set on having on-site power may shy away from wind, as HAWTs require wide, open spaces and VAWTs, while they can be installed on buildings, produce less energy than HAWTs.
Pros
- Minimal emissions from installation
- Rapidly decreasing costs
- Low upfront costs
Cons
- Least predictable renewable energy source
- Can be expensive without subsidies
- Some consider turbines an eyesore
- RP Siegel at Triple Pundit notes that there is concern that turbines can interfere with wildlife such as birds and bats and affect local nighttime temperatures and weather
Waves
Overview
You may be no stranger to the idea of wind and solar, but the movement of the waves you love to splash in or the tides that force you to move your beach chair halfway through the day can also be leveraged for human use. There are several ways to turn the movement of water into energy, known in the renewable world as hydropower. Wave power, which uses the movement of waves to create electricity, is dependent on wind, and is sometimes considered part of overall wind power. Tidal power depends of the movement of the tides, which is linked to factors such as Earth’s rotation, the movement of the Sun and Moon, and the shape of local terrain. The third type of water-based renewable power generation is hydroelectric power, which is most commonly procured through dams. In hydroelectric systems, energy is produced by the movement of water through turbines. Dams are one of the most recognizable styles of hydropower production in the U.S. and are often built of rivers and lakes. Power can also be generated through river diversion, which does not require a dam. Hydropower is found almost everywhere, with the lowest concentrations in Nevada, New Mexico, and Texas. PPAs vary greatly in length, anywhere from 5 to 40 years, and are typically signed between developers and utilities rather than companies on large-scale projects. Hydropower itself is on the whole cheaper and more efficient than solar and wind the 2017 LCOE for dams at USD 0.11/kWh or less, but it suffers from other barriers. Dams are expensive to build, technology for wave and tidal power is relatively new and not as efficient as dams or pumped storage, and all three are geographically limited, as dams need a river and tides and waves need the ocean or other sufficiently large bodies of water. While not as common as solar or wind, there are few small-scale hydropower companies in the U.S., making hydropower a great option for companies looking for smaller amounts of renewable energy or who are trying to build a diversified energy portfolio.
Pros
- Power from hydroelectric dams is among the most reliable of renewables
- Wave energy is less variable than wind
- Tides are more predictable than wind or solar
Cons
- Wave and tidal power is site dependent, meaning that it is very effective at a good site, but sites may be difficult to find and cannot be set up just anywhere
- Dams are one of the most expensive forms of renewable energy in terms of capital expenditures
- Tidal power has high upfront costs
- Dams can harm the surrounding environment by disrupting riparian areas and degrading water quality
Conclusion
So there you have it! Next time you’re on vacation, look around and take in how many natural processes occurring around you have potential for untapped power. In the meantime, what we’ve learned from our beach adventure is that while all three major sources of renewable power have their advantages and disadvantages, solar offers the most flexibility and reliability with low lifetime cost. For a more in-depth exploration of the pros and cons of various renewables, including charts and statistics, check out Solar DAO’s article on Medium. If your company is looking to make a move to solar, contact Holocene Clean Energy for a complimentary assessment of your energy needs and options.