[1] The Solo is an integral midibus (as opposed to a separate chassis and body) built in a modular design, with steel frame and fibreglass panels.

However, the Cummins-powered Solos required extra rear bodywork in order to accommodate the larger engine, which increased the overall length by 0.3 m (1 ft).

Along with the launch of the 9.9 m (32 ft 6 in) model, the Solo was also first offered with LED-type rear lights, as opposed to the standard rectangular clusters.

The compact size of an M780SL, with its seating capacity of 25, has made it a popular choice for replacing earlier-generation minibuses, such as the MCW Metrorider, and other van-based buses.

[needs update] The first SE built, the former Optare demonstrator, entered service with Regal Busways, of Essex, in September 2006.

Optare first experimented with a hybrid electric variant of the Solo in 2004, supplying Solo body shells for Dutch utility company Eneco, who had developed a hybrid drive system consisting of a Volkswagen 1.9 litres (0.42 imp gal; 0.50 US gal) engine paired with a Siemens electric generator.

This combination allowed for a power output of 130 kilowatts (170 hp) and a 30% reduction in carbon dioxide emissions compared to diesel Solos.

Since the summer of 2013, the vehicle uses a high-efficiency MAGTEC P180 Permanent Magnet Motor-Gearbox rated at 150 kW and powered by two banks of Valence lithium-ion phosphate batteries.

It is a completely-restyled version of the Solo drawing styling features from the Versa, such as the curved side windows and sweeping roof (with the destination screen and air conditioning unit underneath).

All 2012 Solo SRs feature curved side glazing and high specification interiors allowing up to 37 seats in the longest derivative.

Some of the bodywork components had been redesigned to take advantage of the benefits achieved on the Tempo SR design, which reduced both weight and cost and further improved fuel economy.

The first-generation electric Solo SR was fitted with a 100 kwh battery pack, giving a maximum range of 90 miles (140 km).

[15] First-generation electric Solo SRs were commonly distributed across rural towns in Scotland with funding from the Scottish Green Bus Fund,[16][17] while a fleet of six electric Solo SRs delivered to Stagecoach Highlands in 2015 for services in Inverness received battery pack upgrades that saw their range increased to a total 130 miles (210 km).

[18] Under Switch Mobility, the first six "next-generation" Solo SRs, with a maximum battery capacity of 135 kWh, were first delivered to Ulsterbus for use in Coleraine, with two of the six being allocated for Giant's Causeway shuttle services.

Between 2014 and 2015, Malta Public Transport leased 23 Optare Solo SRs from United Kingdom lessor Dawsonsrentals as temporary cover while a fleet of new Otokar buses were being manufactured.

[30] In the United States, a left hand drive version of the Solo was sold from 2003 to 2005 by North American Bus Industries (which at the time owned Optare) as the 30-LFN.

[32] In 2012, Optare began delivering the first of 190 Solo SRs for Cape Town's MyCiTi bus rapid transit system.