This page provides a brief overview of renewable energy, solar, wind and energy storage. For more information on renewable energy, depletion of fossil resources, energy and climate change click the link below.
What is Energy?
Energy is the ability to do work.
There are many forms of kinetic or potential energy such as gravitational, thermal, electrical, chemical, nuclear, etc. Energy is often transferred between these forms to perform useful work such as converting the wind into electricity, running a motor on gasoline, or converting food into energy.
Primary energy sources such as the sun or fossil fuels (which are really stored energy from the sun captured by photosynthesis millions of years ago) can be converted into electricity, an energy carrier. We can then use electricity for energy services such as turning on lights, refrigerating our food, pumping our water and charging our cell-phones.
Renewable Energy Sources
Energy sources powered by the sun, wind, water and earth’s heat are considered renewable because they are not depleted as we utilize them allowing for a sustainable future. We use fossil fuels and other non-renewable energy sources at a rate in which their reserves cannot be replenished faster than we attain them.
An idea for the Zero-Energy Solar Laboratory that will soon be build on UVI’s St. Thomas campus.
Some renewable energy sources are intermittent. Since the sun doesn’t shine at night and the wind doesn’t blow all day we cannot produce energy 24/7.
Solar Energy in the VI
In the Virgin Islands we are known for our warm sunny days all year long. The best part is we can use this resource to create affordable energy by placing solar photovoltaic (PV) panels on rooftops or fields.
Fortunately, the cost of solar panels has been exponentially decreasing over the past few years as technology and production continue to improve. In fact, renewable energy sources are comparable if not better than traditional fossil fuels.
“‘Coal is on the way out’: study finds fossil fuel now pricier than solar or wind.”
Wind Energy
Wind is caused by differential heating of the earth’s surface and the rotation of the earth. As air in the atmosphere moves from high pressure to lower pressure regions we feel a light sea breeze, Caribbean trade winds or hurricane force winds.
The power produced by a wind turbine is a function of the swept area of the blades and the wind speed, which is proportional to the height. This is why current trends in wind turbine design is towards becoming bigger and higher.
US VIRGIN ISLANDS ANNUAL WIND SPEED MAP
Wind speeds are measured at the 70 m hub height. Map from National Renewable Energy Laboratory (NREL) US Virgin Islands Energy Roadmap: Analysis (Sep 2011).
Energy Storage
In a traditional centralized electricity grid system, energy production is being constantly adjusted to exactly match the consumer’s electricity demand, the load. This is because storing electricity has proved quite a challenge. However, with the rise in popularity of intermittent distributed renewable energy generation, energy storage has become an important topic.
While there are a range of potential energy storage technologies, the Virgin Islands has mainly considered batteries such as Lead-acid, Lithium-ion, Nickel metal hydride and flow batteries.
Other possible forms of storage could include small-scale pumped hydro or thermal storage.