By Sarah Lozanova
Most of us think of solar energy as consisting of photovoltaic solar panels, which make up 95 percent of the solar energy market. Solar towers, however, are proving to be a promising technology for commercial-scale installations as well.
Construction is now underway on the Ashalim Thermal Solar Power Station, where a vacant stretch of the Negev desert in Israel will be home to a 787-foot solar tower.
This is a big step in achieving Israel’s goal to source 10 percent of its energy from renewables by 2020. The solar tower will produce enough electricity to power 121,000 Israeli homes, or meet 1 percent of Israel’s total electricity needs. Although the project is privately funded, the Israeli government has agreed to buy the power at above-market prices. Construction is expected to conclude late next year.
Google is leading the clean-energy revolution like no other company. It has invested in 22 renewable energy projects to date. In fact, Google is the biggest corporate purchaser globally of renewable energy, with a hand in utility-scale wind and solar projects that span the globe. Google has a goal to power 100 percent of its operations from renewable energy, and it is well on its way.
“We’re really trying to lead this transition to a cleaner energy economy,” said Michael Terrell, principal for energy and infrastructure at Google. “It’s transforming anyone who touches the energy space. It’s not just about data centers or tech companies.”
The Google approach to renewable energy is not unlike how many utilities purchase power. It often enters into power purchase agreements: long-term financial agreements, typically with wind farms, to buy power. The projects that Google has been involved with span the globe, including in Sweden, Iowa, Oklahoma and California, along with a recent $12 million investment in the largest solar energy project in South Africa.
by Sarah Lozanova
Installed solar energy capacity in the U.S. is growing dramatically, with numerous record-shattering years in a row. There is now enough installed solar energy to power over 4.6 million U.S. homes and a new solar project is installed every two minutes. Meanwhile, the cost of solar has fallen significantly, helping to fuel this unprecedented growth.
Solar energy (r)evolution
Since 1998, the cost of residential and commercial solar photovoltaic (PV) systems has fallen every year by an average of 6 to 8 percent, according to the National Renewable Energy Laboratory. Since 2006, the installed cost of solar energy has dropped more than 73%. Once a market dominated by environmental motives, many people are now installing solar PV to save money.
This 36-unit community may be the nation's first planned development built around Passive House green building standards.
By Sarah Lozanova
Even from the layout of the homes, visitors can tell something is unique about Belfast Cohousing & Ecovillage. “Where are the driveways?” one guest asks. “How strange, these houses don’t have any driveways!”
Belfast Cohousing & Ecovillage (BCE) is a 36-unit intentional community on 42 acres in Midcoast Maine. Members designed the community from 2008 to 2011, before breaking ground in 2011; GO Logic, a Belfast-based design-build firm that specializes in sustainable building, designed the units and site plan and served as general contractor.
The homes are clustered, and a pedestrian path, not a road, runs through the six-and-a-half-acre built area. Despite being a rural property, all the homes are located in two- to four-unit buildings and range from 500 to 1,800 square feet with one to three bedrooms. The community layout encourages social interaction, offers safety for children, and provides open space for food production, wildlife and recreation. With PV solar systems, these highly efficient homes are near net zero.
PASSIVE HOUSE DESIGNS
When one enters the homes, it becomes obvious that the lack of driveways is only one of many differences between these houses and the average code-built home. Despite being located in Midcoast Maine, the houses have no furnaces.
Until several years ago, most residential photovoltaic (PV) systems were purchased. Because of the upfront cost (and because solar systems were more expensive back then), there was a very limited pool of potential solar system owners.
Around 2008, solar leases or power purchase agreements started growing in popularity. This was a game changer in the solar world, because it helped remove financial obstacles. Suddenly people could have solar on their homes for as little as no money down, and often pay less each month for their electricity.
In the last couple years, solar loans became available with more appealing terms. Suddenly people could get a relatively low interest loan with a 20-year term. This again can be a game changer for the industry because the loan payments are in many cases less than the reduction in the electric bill.
So you may wonder, is it better to lease or own. Of course the answer is: it depends.
By Sarah Lozanova
Inspired by the concept of making a sustainable lifestyle easier, GreenPod creates low-maintenance modular homes with healthy interiors.
Factory-built kits can be transported to a building site and easily assembled. Using state-of-the-art technology and materials, these homes have a small footprint and conserve both water and energy. The homes, including tree houses and floating homes, are customized to the site, have passive solar features and minimize site disturbance.
The walls, floor and roof of the homes use SIPs (Structurally Insulated Panels), with a rain shield on the exterior. “The homes are precut when they come out of the factory, so they can go up in a day or two on the site,” says Ann Raab, GreenPod’s founder. “SIPs are the best bang for your buck. Although they are slightly more expensive than a stick built home, SIPS have a short 2.7-year payback. They are stronger and straighter than wood, with no job waste [because the SIPs are precut]. Everything about SIPs delivers what we are trying to create.”
Raab has a vision to simplify green building, while making sustainable living affordable for the mainstream. GreenPod homes are customized to fit a variety of budgets, with optional features including: locally-crated furniture containing organic textiles, reclaimed building materials, solar panels and a biofilter refrigerator.
By Sarah Lozanova
Our homes can be comfortable and energy-efficient: Especially if we borrow from the high-performing, effective ideas used around the world in “passive houses.” Developed by the German Passivhaus Institut in 1996, a Passivhaus is defined by core efficiency standards. What does this mean in practice? Homes built to the Passive House standard are extremely comfortable to live in—with natural daylighting, even temperatures throughout and virtually no drafts.
Passive homes require 90 percent less energy to heat because energy losses are minimized with generous amounts of insulation and air sealing. The homes are heated largely by solar heat gains and internal gains from people and electrical equipment. Although fully retrofitting a home to the passive house standard is usually very costly, we can use many of the elements of passive home design to make our homes more efficient. Apply the following concepts to your home to boost comfort and reduce energy bills.
Boost Winter Solar GainSouth-facing windows and, to a lesser extent, east- and west-facing windows help gradually warm our homes with solar energy. Maximizing this free energy source reduces dependence on heating systems, in turn lowering utility bills in cold climates and promoting indoor air quality. Forced air heating, for example, can carry dust with the heat as it passes through duct work, while wood-burning stoves and heating systems that use natural gas or propane can emit carbon monoxide. Wood-burning stoves also can produce breathable pollutants such as smoke and ash.
Clean southern windows and remove screens. When the heating season begins, remove screens on south- and east-facing windows and wash the windows to increase your solar gains by up to 40 percent. Keep screens in the west- and north-facing windows to provide protection from the winter wind.
Avoid shading southern windows in the winter. Evergreen vegetation, carports and porches can shade southern windows, hindering solar gains. In colder climates, plant only deciduous trees and shrubs (which lose their leaves in winter) outside south-facing windows, or space vegetation and structures far enough away from the house to avoid shading southern windows.
Expand with a solar addition. If you are planning an addition on your home, consider adding a sunroom, which can help heat your home. Effective sunrooms face south, include lots of thermal mass, are thoroughly insulated, and include ventilation options with windows, doors and skylights.
Freelance clean energy writer