Solar-powered home in the works
For centuries, Cayman residents have used kerosene, propane, and, more recently, natural gas and diesel to power their homes, without having to hook up to the Island’s electricity grid.
But all of these power sources have something in common – they are fossil fuels, meaning that when they burn, they create carbon dioxide emissions, which scientists have connected to global warming and climate change.
Cayman resident and local innovator Jim Knapp, a former physics professor who works as Butterfield Bank’s chief technology officer, is planning to build a new kind of self-powered home – his house will be emissions-free.
‘I think that no matter if you believe humans are having an impact on climate change or not, I want to do my part in reducing my emissions for the good of the planet,’ says Mr. Knapp.
‘And I can tell you right now it’s going to be saving me money by not having to pay for electricity.’
His new home, now in the final design phase, is Cayman’s first ever solar-hydrogen powered home.
‘We have talked to all the people that are needed to get this done, from Planning, to the Department of Environment, to the gas people, to CUC, so that we can get this project off the ground – I want it to be a showcase of what can be done here in Cayman when it comes to clean energy technology,’ says Mr. Knapp.
The system that will be powering Mr. Knapp’s home is designed by New Jersey’s Renewable Energy International, and it relies on Cayman’s estimated 320 days of sun a year.
It’s a fairly simple process: 56 photovoltaic solar panels on the home’s roof collect energy from the sun’s rays and convert it into a direct electric current, which passes to a battery bank. The current from the batteries then passes through an inverter that changes it from DC to AC, a conventional current used for all household appliances.
Overflow energy from the solar panels flows to a different device called an electrolyzer, a tank full of water, where the current is used to separate the hydrogen and oxygen from water. While the oxygen is released into the air, the hydrogen is collected in a 1000 gallon tank below ground, where it can be stored until it is needed.
If the house does require power to be produced from the stored hydrogen, the gas will flow into a hydrogen fuel cell, which acts like a solar panel in that it creates a current that can then pass to the same battery bank used by the solar panels. That way, the hydrogen system can provide energy for the home at night, and for up to 15 days of sunless weather – a rarity in Cayman.
Mr. Knapp’s home is unique in that it is only the second such residential system in North America. In fact, Mr. Knapp heard about REI after the first home, a retrofit, received press coverage at the time he was considering clean technology options.
REI says Mr. Knapp’s home will demonstrate the system’s significant cost and environmental benefits for a sunny island like Cayman, especially one that relies on imported fuels.
And even in the event of a hurricane or other disaster, a system such as Mr. Knapp’s can provide backup power without any supply line dependency or interruption.
‘We have the ability to replicate this system for remote homes, commercial buildings, for backup storage for essential community buildings such as hospitals…and eventually entire communities. We hope to set an example here for all island communities to follow,’ says Michael Strizki, inventor of the REI solar-hydrogen system.
But the hydrogen-solar power system isn’t the only thing that makes this home unique.
To increase energy efficiency, the system will be integrated with Cayman’s first geothermal home cooling system that will use up to 70 per cent less energy to run than a conventional one.
Using a closed-loop system of pipes containing a special type of refrigerant, heat from the home is collected and transferred to the ground instead of back to the air outside (the way conventional air conditioners do). Likewise, the cool ground temperature makes it easier for the machine to cool the home, and strategically placed fans increase efficiency.
‘I’ll be able to run my A/C 24 hours a day, completely guilt-free,’ says Mr. Knapp.
The ultra-modern home will feature the latest in energy-efficient construction including solid concrete construction with foam block insulation, high-efficiency windows and doors that will block air seepage and heat, and LED lighting that uses a fraction of the energy of conventional lightbulbs.
Energy efficient appliances will also be installed at the home to reduce the overall electricity load.
The price for the system, though seemingly hefty at US $165,000, forms part of the 3,000-square-foot home’s construction costs and will be assimilated into Mr. Knapp’s mortgage.
‘I can in fact do this, and as a part of my mortgage payments, it’s going to be more affordable than paying my CUC bill – it’s a bankable transaction,’ he says.
Despite Mr. Knapp’s ability to run the home without help from CUC, he has made the decision to connect to the grid all the same.
‘Currently, CUC does not allow any on-grid or directly connected electric generation devices to connect with CUC’s electric grid,’ says a CUC statement.
‘Looking forward, CUC is seeking a new electricity license agreement with Government and on-grid electric generation systems may become future choices for our customers.’
The statement says that off-grid electric generation devices are allowed by law and CUC as long as the electricity produced is not used for resale or sharing for free or profit.
It also states that neither the Electricity Law nor CUC restricts or prohibits persons from producing electricity for their sole use and consumption. Although, persons who produce their own electricity and wish to use CUC’s electricity grid as a standby supply may be subject to additional fees to cover the cost of CUC’s service equipment, installation, and maintenance.
Mr. Knapp says CUC has in fact been supportive with planning the project, from gathering information on clean energy technologies, to getting hold of the right equipment.
Engineering services manager Sacha Tibbetts says the company has been exploring alternative energy options for some time.
‘We are very interested in working with him in helping him realise the goals of the project,’ says Mr. Tibbetts.
‘We think that his choices of technology are very interesting and we would like to help him out in making it work.’
Mr. Knapp says his home can act as a test project.
‘In the eventuality that I could sell my power back into the grid one day, I’m even better off when it comes to the return on investment, and they would work with me to make it happen,’ he says.
Not surprisingly, Mr. Knapp also has the support of the Department of Environment.
‘Given the challenges posed by climate change for our islands, the Cayman Islands Department of Environment very much supports the use of renewable sources of energy,’ says Director Gina Ebanks-Petrie.
‘We are extremely pleased to see private individuals taking the initiative in this area. The Cayman Islands Government has recently signed the United Nations Framework Convention on Climate Change and its Kyoto Protocol, so a national discussion needs to take place in the very near future on, among other things, the appropriate mix between renewable and traditional energy sources in meeting the country’s demand for electricity. ‘
The solar-hydrogen technology is available to all homes on the island.
‘There is no reason anyone else on the Island can’t do the same either when constructing a new home or by doing a retrofit.. It’s completely worth it in the long run as you are doing your part not only for the planet but also for your pocketbook,’ says Mr. Knapp.
‘And I’m going to prove it with this house.’