Tuesday, 11 August 2015

Solar PV Still Cost Effective

A 4kWp system can generate around 3,800 kilowatt hours of electricity a year in the south of England – roughly equivalent to a typical household's electricity needs. It will save nearly two tonnes of carbon dioxide every year. A 4kWp system in Scotland can generate about 3,200 kilowatt hours of electricity a year – more than three quarters of a typical household's electricity needs. It will save more than a tonne and a half of carbon dioxide every year.
System size
Feed-in-Tariff generation payment (£/year)
Feed-in-Tariff export payment (£/year)
Electricity bill savings (£/year)
Carbon dioxide savings (kgCO2/year)
Valid between 1st April - 30th June 2015Valid between 1st July - 30th September 2015
London, South England4kWp£510£495£90£1351,870 kg
Aberystwyth, Wales4kWp£480£460£85£1251,750 kg
Manchester, North England4kWp£450£435£80£1201,650 kg
Stirling, Scotland4kWp£425£410£75£1101,560 kg
The average domestic solar PV system is 4kWp and costs £5,000 - 8,000 (including VAT at 5 per cent). 
When Fits (Feed-in Tariff ) were first launched in 2010, a typical large domestic photovoltaic system cost £15,000-£18,000 to install. Early adopters were promised 41.3p per kilowatt hour (kWh) generated for 25 years, plus generous savings on their electricity bills worth up to £160 a year. Incomes and savings of more than £30,000 were promised for a £15,000 investment.

Price falls in PV panels over the past five years mean that the same system can now be installed for £5,000-£6,000 – and the government has responded by cutting the income paid accordingly. Those installing a system before 30 September this year now receive 12.92p per kWh if they live in a home that is energy performance certificate band D or above.
You still need a south facing, unshaded roof, ideally at a 45-degree pitch. Those who live in the south will get the highest income. Someone installing a £6,000 panel system on such a roof in Hertfordshire can expect an income and electricity bill savings of around £600 a year. Payments are index linked and are guaranteed for the next 20 years.
For an accurate calculation of how much your roof will generate use the EnergySavingsTrust calculator.

Tuesday, 4 August 2015

Apple's HomeKit

The first products to take advantage of Apple’s smart home technology were unveiled today, just days before the start of the company’s Worldwide Developer Conference.

Five device makers announced products that dim the lights or adjust room temperature with a spoken command or control fans and other home appliances from the iPhone, iPad or iPod touch. Two products are available now, with others reaching stores in the coming weeks.
IHome, a maker of iPhone- and iPod-compatible clock radios and audio accessories, said its first HomeKit product would begin reaching stores in late June. Its SmartPlug allows consumers to use Siri to control their lighting, fans and other home devices.
Lutron Electronics’ Cas├ęta Wireless Lighting Starter Kit provides wireless plugs, remote control dimmer switches and a smart bridge, which allows homeowners to adjust their lights (and, in some cases, the window shades and thermostats) without leaving their couches. Its software will even send a notification if the homeowner has left without turning off the lights. It is available now.

Toronto-based Ecobee announced that its wireless thermostat now works with HomeKit, allowing users to adjust their heating or cooling using Siri on their iPhone or iPad, while Insteon’s HomeKit-compatible hub lets consumers control a range of home gadgets, from door locks and garage door openers to lightbulbs. HomeKit is on sale today online.
HomeKit is a system for connecting smart home devices through iOS.
Apple allows for either WiFi or Bluetooth low energy (LE)-enabled devices to get certified as a HomeKit accessory. Apple is requiring device makers using both WiFi and Bluetooth LE to use complicated encryption with 3072-bit keys, as well as the super secure Curve25519, which is an elliptic curve used for digital signatures and exchanging encrypted keys.
“These security protocols are bleeding edge,” said Diogo Monica, a security lead at Docker and an IEEE security expert.
WiFi-enabled devices can handle these security requirements, but it seems devices running over Bluetooth LE are having some issues. The intensive processing demands for generating and sending these security keys is what’s likely causing these lag times.

Such lag times render many of these devices useless. For example, a smartlock that makes its user wait 40 seconds before it opens is clearly inferior to a traditional lock. One of HomeKit’s selling point is that it provides a more reliable user experience, so these kinds of lag times will need to be sorted out before Apple can become a major platform for the smart home.

People with an August smart lock fitted to their front door can now use an Apple Watch to lock and unlock their home with 'just a swipe and a tap'.
The watch app also tells users who has recently come and gone as well as receiving a notification when someone enters of leaves their house.
The August lock is made of 'durable anodized aluminium' and can be managed using the app which works on a smartphone and Apple Watch, as well as online.
Owners of the lock, created by technology entrepreneur Jason Johnson and industrial designer Yves Behar, can already lock and unlock their door with their iPhone, but the watch will make the process more convenient, because the 'digital key' is already on their wrist.
The battery-operated lock, which launched last year, costs $249 (£160) and its makers claim, takes just 10 minutes to install.
It includes deadbolt adapters and faceplates that work with around 90 per cent of locks on the market in the US.
The encrypted locking technology issues registered devices such as smartphones or the Apple Watch, or invited devices, with unique codes that can't be copied.

Sunday, 2 August 2015

Obama's clean energy plan expected to boost renewables

After a year of consultations and over 4 million public comments, President Obama's Clean Power Plan will be finalised early next week.

The strategy will outline restrictions on CO2 from electricity that individual states will have to implement.

The EPA said that emissions from electricity generation need to be reduced by 30% of the 2005 level by 2030.

At that time the EPA said that individual states need to get their plans in place by 2016 and they were to become operational by 2020.

But after consultations with industry, states and 4.3 million comments from the public, the EPA is likely to extend the deadline for the start of carbon cutting until 2022.

The thinking appears to be that a shorter deadline makes it more likely that states will switch from coal to natural gas, as they have been doing in recent years.
It's expected that there will be increased support for solar, wind and other renewable sources

A longer timeframe supports the view that energy efficiency, renewables and emissions trading between states could all play a greater role, and result in bigger carbon savings over time.

Experts believe that the delay will come with some sweeteners to encourage the take-up of renewable energy sources like wind and solar.

International observers are keenly awaiting details of the plan, to see how it might affect UN-sponsored talks on climate change, that are due to agree a new global treaty later this year.

The US has put forward a proposal to cut its overall emissions by 26-28% of their 2005 levels by 2025. The widespread acceptance and implementation of the electricity plan is vital to achieving this target.

Follow Matt on Twitter @mattmcgrathbbc.

Most Green Fuel Efficient Car

Today the selection of efficient, lower-pollution cars includes a bewildering array of technologies and models — hybrids, plug-in hybrids, battery electrics, diesels and hydrogen fuel cells. Conventional gasoline cars, meanwhile, have made great strides in going farther on less fuel.

Battery electric cars — those that run solely on electricity — are the cleanest and least expensive to operate. But they typically get only about 80 miles of driving range on a full charge (Tesla's Model S is the exception, traveling more than 250 miles on a charge, but it typically sells for about $100,000.)

"Electric vehicles are the greenest choice for California drivers," said Dave Reichmuth, senior engineer at the Union of Concerned Scientists. "But even switching to a more efficient gasoline vehicle can lead to significant emissions reductions and lower petroleum use."

Battery electric

For the true environmentalist, nothing beats an electric car charged by renewable energy sources. Homeowners with rooftop solar panels can literally drive on sunshine. Electric car buyers also get generous state  subsidies.

But even electric cars powered by the grid produce less carbon emissions than other vehicles. More surprising, the efficiency doesn't necessarily exact a penalty in performance.

"A lot of people don't realize that the electric motor has a lot more torque from a stop, which means the cars can be fun to drive," Reichmuth said.

But there are drawbacks. All but the Tesla have ranges under 100 miles. They can take hours to charge. They are generally more expensive than a similar gasoline vehicle.

Hydrogen fuel cell

Hydrogen powered cars are finally entering the U.S. auto market after years of anticipation. Hyundai is leasing its Tucson fuel cell vehicle to consumers who live near the handful of hydrogen stations in California. 
Like electric cars, fuel cells are expensive but come with generous government subsidies to buyers. The bigger obstacle for buyers will be fueling infrastructure — just 20 stations are expected to be in operation in California by the end of this year.

Because natural gas is used to make most hydrogen, fuel cell cars are also not as clean as battery electrics. On the plus side, they can be fueled up as quickly as gasoline vehicles and have a range of about 300 miles between refills.


Although popular in Europe, diesel has never caught on in the U.S. You see it stateside in German passenger cars, domestic pickup trucks and in commercial trucking. But modern diesel engines are cleaner, less noisy and more efficient than they have ever been.

They also offer a great driving experience and ranges of more than 500 miles, making them ideal for those with long highway commutes. When it comes to carbon emissions "diesel pencils out about the same as an efficient gasoline car but not quite as efficient as the hybrids," Reichmuth said.

Compressed natural gas

Once thought of as a promising transitional technology on the road to hydrogen and electric cars, compressed natural gas cars have driven into a dead end. Honda is discontinuing its natural gas Civic after the current model year, and no other automaker is stepping in with a passenger car that runs only on CNG.

Natural gas cars are only a little more polluting than a comparable hybrid, and they are less expensive to fuel. But the CNG tanks take up too much space, limiting the size of the cabin and trunk, and their driving range is limited. The CNG Civic travels less than half the distance on one fueling than the gasoline model and only a third of the hybrid.


With the exception of the Toyota Prius, hybrids have never achieved the popularity some environmental groups and auto industry analysts expected. A variety of factors hold back sales. For instance, to reduce weight and improve fuel efficiency, automakers have removed sound deadening materials, allowing road and wind noise into the cabin, especially at highway speeds.

Hybrids cost more than regular cars. With the average price of regular gasoline now well under $3 a gallon nationally, the payback period on gas savings can be long.

Still, hybrids are a great choice for those who drive many miles — especially in stop-and-go traffic, when the cars recapture energy during braking to power electric motors that help propel the car and save gas. . A compact hybrid generates about 240 grams of carbon dioxide per mile, or just 55% of the amount generated by a conventional gasoline car that gets 25 mpg.

Some are exceptionally well done. The Honda Accord hybrid is a full-size, family sedan that gets 47 mpg in combined driving and goes more than 550 miles between gas station stops.

Plug-in hybrid

Plug-in hybrids run on electricity until their batteries are drained and then switch to gasoline. They're the Swiss Army knife of green cars.

Diesel engines are cleaner, less noisy and more efficient than ever. Above, a diesel-powered Audi A3. (Tribune News Service)
The Volt has an all-electric range of 38 miles. As a group, Volt owners drive about 60% of their miles on electricity alone. Many drive nearly exclusively on electricity, using the gas mode only for long-distance trips. That's why Volt carbon emissions approach the levels of fuel cell vehicles and battery-only electric cars. It's also one of the least expensive vehicles to operate. Just $6.83 in power and fuel will take you 100 miles. Those numbers are expected to improve for owners of the next generation Volt, which comes out this year with an all-electric range of 50 miles.

But not all plug-in hybrids are equal. The Prius plug-in has an all-electric range of just 11 miles, making it barely useful for running the children back and forth to school. The all-electric mode on the Accord plug-in is just 13 miles.


Don't write off the internal combustion engine as an efficient option, especially until automakers can make alternative drivetrains less expensive and more practical. Automakers have greatly improved gas mileage in recent years and offer a wider range of economical gasoline models.

These vehicles also cost less to buy than those with alternative fuel , although they produce about a third more pollution per mile than a comparably sized hybrid.